As the development of the laser processing technology, the laser printing technology is extensively applied to the fields of electronic composition, laser plate making and so on, greatly simplifying the printing technology. The digitization of the laser printing technology can realize a remote plate making and printing, thereby speeding up the press and publication, and also economizing the cost and human input on a large scale. The laser applied to the field of printing enables a rapid development of the printing industry.
The realizing of the laser printing technology not only depends upon a widespread use of the fiber laser, but also profits from the continuously upgrading of parameters of the optical focusing system. The laser printing device generally has a focusing lens, and the focusing lens is desired to have a large relative aperture and a large visual field angle, and is expected to have a longer working distance. Existing focusing lens applied to laser printing generally adopts microscope, and focuses the ultraviolent laser. Though the microscope has a large relative aperture, but the visual field angle is small, the working distance is short, and the operation is inconvenient, thus affecting the focusing effect, and further affecting the printing quality. The printing precision and clarity are not ideal and the color rendition is not true. Therefore, it is desired to provide a new focusing lens applied to laser printing.